A DNA Typewriter records the cell lineage history of a mouse, from zygote to late organogenesis.

DNA Typewriter reconstructs a time-calibrated phylogeny of 1.28 million cells in a mouse from zygote to late organogenesis, revealing developmental lineage relationships.

• Why it matters: Understanding mammalian development at the cellular level is limited by tissue opacity and technical challenges, hindering insights into cell lineage and differentiation pathways.
• What they did: The study applied DNA Typewriter to record cell lineages over nearly two weeks in a mouse embryo, generating a detailed phylogeny supported by transcriptional profiles and clonal analysis.
• The result: This approach uncovers clonal dominance during gastrulation, shows that tree siblings share cell types more than expected, and reconstructs a lineage-based ontogeny, advancing our view of mammalian development.